As a method of mounting a semiconductor component on a board, there is a solder bonding method in which a bump formed of solder on the undersurface of the semiconductor component is coupled to an electrode on a circuit board for conduction. However, solder bonding of a bump with an electrode alone often provides an insufficient retention force that retains the semiconductor component to the circuit board. In this case, a thermosetting resin such as epoxy resin is used to reinforce bonding between the semiconductor component and the board.
As a resin-reinforcing method, such as solder fill and side fill are developed (refer to PTL 1, for example). Another technology is developed in which a resin-reinforcing solder paste is used that is a composition of thermosetting resin containing solder powder and a flux component (refer to PTL 2, for example). Still another technology is developed in which resin composition free from solder is deposited onto the surface of a solder ball (refer to PTL 3, for example).
A description is made of an example of related resin-reinforcing methods, referring to FIGS. 23A through 23C. FIGS. 23A through 23C are sectional views of an example of related surface mounting using a resin-reinforcing solder paste.
As shown in FIG. 23A, thermosetting resin composition 1 is preliminarily printed onto electrode 3 formed on the surface of circuit board 2. Then, sealant 5 is applied onto the surfaces of circuit board 2 and thermosetting resin composition 1 using syringe 4.
Next, as shown in FIG. 23B, semiconductor device 6 is mounted onto circuit board 2 with sealant 5 applied thereonto. In detail, terminals 7 formed on one surface of semiconductor device 6 are pointed toward circuit board 2, and semiconductor device 6 is landed on circuit board 3 as indicated by the arrows.
Subsequently, as shown in FIG. 23C, circuit board 2 and semiconductor device 6 are heated, and bonding part 10 is formed of solder part 8 and resin-hardened part 9. FIG. 23C is a sectional view of semiconductor device 6 after mounted.